Balanced let-off for looms



y 7' 1927' w. H. WAKEFIELD BALANCED LET-OFF FOR LOOMS Filed Oct. 17. 1925 Patented May 17, 1927.

UNITED STATES PATENT OFFICE.

WALTER H. :WAKEFIELD, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CBOMP- TON & KNOWLES LOOM WORKS, F WORCESTER,.MASSAGHUSETTS, A COBPORA- 'IIOlV 0F MABQAGHUSETTS.

BALANCED LET-OFF FOR LOOMS.

Application filed, October 17, 1925. Serial No. 63,175.

This invention relates to let-oil? mechanism for looms and more particularly to a device which will permit a let-back of the warp for the removal of a mispick in heavy looms for weaving such fabrics as duck.

In the weaving of cloth it not infrequentl hap ens that a short end is left in the shed w ich must be removed by the weaver. Under such conditions the take-u is reversed to slackenthe cloth so that t e picks laid after the mispiok occurred can be re moved. Afterthe pick-out is completed it is necessary to restore the original tension on the warp threads and it is the general object of my invention to provide improved means by which the original tension may be restored to the end that a mark will not be left in the cloth.

It isa more articular object of my 1:nvention to provj e a pair of balanced devlces each capable of exerting the same tension on the warp, one being normall idle and l the other normally operative, sai other device being acted upon to cause ncreased tensionso that the first devlce only may operate. A motion of this general char actor is set-fob h in co-pending a lication Serial No. 63, 77 tiled by George Hutch- ,ips and in that application there is shown a weighted roll normally held n stationary position anda friction drum, the warp assall around hoththe drum and the weig ted .re 1. The rollis nermally stationary and the forward movemept of the warp ISMIG- sisted by the friction of the drum only. At the time of a ickont addltronal frlctton is placed on. thergnnmso that the same is held stationary and a the Weighted roll is lowered to. take u slack. the subsequent weaving ll'estoring tie weighted roll to ts normal position. In said application the additional ifrietian is applied by means of auxiliarv brake levers controllable by the pperator and aetaatedto operate at the t me the weighted toll is released. It is a .more particular object'of my lnventlon to ;make use of the usual form of fr ction and dispense with the aux l ary brake levers employed 7 said applicat on. The usual form of f r 'iction comprises a contnol lever extending toward the front of the loan: and posit ianed vertically. a screw m many the tcmaon .of the ,Erretaon hand l the. lo mconnected thereto as at 20 the lower end of an adjustable link 21 the upper end of which which extends around the friction head of thevvarp drum. I propose to apply the additional friction which will arrest movement of the drum merely by raising the control lever and holding the same in elevated pos1t1o n the weighted roll being released by an auxll ary hand lever conveniently located on the control lever and operable to release the Weight after the additional tension has been placed on the drum.

W'ith these and other objects in view WlllCll will appear as the description roceeds my invention resides in the combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings wherein I have shown a convenient embodiment of my invention,

*ig. 1 is a front elevation of a portion of a loom havin my im rovements applied thereto and showing tie same in normal running position,

Fi 2 is a View similar to Fig. 1 but showing the parts moved to permit the taking up of excess warp incident to a pick out,

3 is a horizontal section on line 33 of 1g. 1,

Fig.4 is an enlarged horizontal section on line.44; of Fig. 1, and

Fig. 5 is a vertical section on line 5-5 of Fig. 4.

Referring more particularly to the drawings it will be seen that I have provided a loom frame 1.0 having mounted at the rear end thereof a drum 11 to the ends of which are secured friction heads 12. Each head has partly wrapped theroaround a flexible friction band 13 anchored at 14- to a fixed part of the loom and connected as at 15 to an adjustable link 16. Each link l6 is pivotally connected as at 17 to a depending arm 18 secured to a shat t .19 extending across One of said arms 18 has pivotally is pivotally connected to a lever 22 fastened to a stub shaft 23 suitably j ournaled in the loom frame. Said stu shaft extends through the frameand has the inner end A stand is bolted. to the front of the loom and has spaced arms 26 through which extends a screw 27. A block 28 is threaded on the screw and has the rear portion thereof flattened as at 29 to engage the adacent up right portion '30 of the stand 25. A hand wheel 31 is secured to the screw to afford means for turning the same and collar 32 prevents upward displacement of the screw. The block 28 as shown in Fig. has an oilset notch 33 on which the lower edge of the controller lever 2a normally rests.

Pivotally mounted on controller lever 25L is a hand lever 34 having an upstanding arm 35 to which is pivotally connected a rod 36.

A flexible chain section 37 is connected to the rod 36 and extends over a sheave 38 1 mounted on the frame in such a way that the center of the chain is in alignment with theaxis of the stub shaft 23. The flexible section 37 is connected t a second rod 39 V to another chain section 420 which extends around a sheave a1 rotatable on a fixed stud 42. The second flexible section or chain lO is connected by means of a third rod 43 to the lower end of an arm 44 secured to a .shaft 45 extending across the rear of the loom. Latch levers 46 are secured to the shaft 45 and each of said latch levers is provided with a notch 47. Bracket 48 is secured to the rear end of the loom and forms a support for cross shaft 47.

A relatively heavy frame 49 is pivoted at the forward end thereof to fixed studs '50 and has the rear end thereof provided with a. detent 51 proportioned to enter notches 47 on the latch levers. Variable weightsjW may be attached to the frame to vary the weight of the same and there .is interposed between the opposite sides of said frame a relativelyrheavy roll 52 piv I otally-mounted on the frame and free to retate thereon.

The warp threads T extend from a creel located behind the loom, over guide bar 53, under drum l1 and guide bar 54, over guide rod 55, under roll 52, and over a fourth guide bar 56 tothe lease rods 57 and other weaving instrumentalities. A tension spring 58 is interposed between each of the latch levers and the bracket 4.8 to hold the parts in the position shown in Fig. 1 and each of y the arms 18 is normally held rearwardly by a spring 59 which also seats the controller lever 24.- in thenoteh 33. A torsion spring '60 may be interposed between a stud 61 will be stationary to cause the warp to move therearound against the friction existing lH. tween the flexible bands 13 and their associated friction heads which more with the drum ll. heads by the bands varied by the screw 27 to produce a fabric ha vine the same num ber oi picks which would he laid wci'e the drum held stationary and thc lAIlsiou applied. to the warp threads by meansof the released weighted roll At the time olf pick-out the detective picks will he rcmovcd, the take-up (not shown) being rclcascd to facilitate this operation and caus ng; :1 1c sultant slack in the warp. At'lcr lhc faulty picks have been removed the talic-up is again tightened and the hand lcvcr ll dcpressed to the JOSlllOl] shown in Fig. 2 by the operator. The effect of this is to move the latch levers 1-6 to the position shown in Fig. 2 to release the weighted frame if). The take-up may then be reversed until the fell of the cloth is in position for the resumption of weaving, after which the loom may be started up and the weaving of cloth continued. This will leave the weighted roll 52 in lowered position and in order that it may be raised to normal position the weaver will elevate controller lever 24 slightly which, through the action of arms 22 and 18, will cause additional friction to be applied to the friction heads through the friction bands 13. This additional friction is sufficient to prevent the rotation of drum 11 and as weaving continues the Weighted roll 52 will be raised by the consumption of the excess war; until the same is in normal position, at which time the weaver will lower lever 24 onto the block 28 and release hand lever 34. This will lock the roll 52 in fixed normal position and willrclieve the extra.

tension on the friction heads so that weaving time and each capable of exerting the same tension on the warp thrcmls. the normally acting device being: of the usual form and subject to a temporary excess tension at the will of the operator to cause functioning of the other or normally idle tension device. It will be seen that the relation of the chain 37 and the axis of the stub shaft 223 is such that adjustments of the controller lever 2t by means of the screw 27 will not disturb the locking of the frame 49.

Having thus described my invention it will be apparent that changes and modifications may be made therein by those skilled in the art without departing from the spirit The friction exerted against the T till and scope of the invention, and I do not wish to be limited to the details herein disclosed but what I claim is:

1. In a let-oif mechanism for looms, two independent tensioning devices each adjustable and each capable of exerting the same tension on the warp threads, one of said devices being normally operative to tension the warp and the other being normally idle, means to adjust the tension of the normally operative device, said means being movable from any adjusted position to increase the tension of the normally operative device when the normally idle device is operative, and manually controlled means mounted on the first named means to render said normally idle device operative.

2. In a let-off for looms, a normally idle device capable of exerting adjusted tension on the warp threads, a normally operative device to tension the threads, means to adjust the tension of the normally operative device to exert the same tension as that which the normally idle device is capable of exerting, said means being movable to increase the tension of the normally operative device, and mechanism controllable from said tensioning means to render the normally idle device operative when the tension of the normally operative device is increased.

3. In a let-ofl' device for looms, a normally idle device to exert an adjusted tension on the warp threads, a lock to hold the same normally idle, a normally operative device to exert tension on the warp threads, means to adjust the tension of the normally operative device so that the latter will exert a tension equal to any adjusted tension which the normally idle device is capable of exerting on the warp, said means being movable to increase the tension of the normally operative device, and mechanism a portion of which is movable with said means to move the lock to unlocking position when the tension of the normally operative device is increased.

In testimony whereof I have hereunto afiixed my signature.

WALTER H. WAKEFIELD. 

